Designers and engineers left almost no bolt unturned during the comprehensive redesign of the trucks. Longer wheelbases and wider front/rear tracks enhance the ride and handling characteristics of the Sierra 2500HD and 3500HD, giving them a greater feeling of smoothness and control.

Offered in 2WD and 4WD Work Truck, SLE and SLT models and in single- and dual-rear-wheel configurations, GMC shows that it is ready for almost anything. Outside, the 2014 Sierra 2500HD and 3500HD models are distinguished by a power dome-style hood with a louvered design, as well as a full-width chrome steel front bumper. A lineup of 17-, 18- and 20-inch wheel/tire combinations is featured, too (20-inch polished forged aluminum wheels are available on 2500HD).

Standard power for the Sierra HD is generated by the venerable Vortec 6.0L V8 engine. Torque is communicated through the wheels by a strengthened version of the Hydra-Matic 6L90 six-speed automatic transmission. The available Duramax 6.6L V-8 direct-injection diesel engine is joined to a robust Allison 1000 six-speed automatic transmission.

The 2014 GMC Sierra HD rides on a rigid frame which includes 11 fully boxed frame assemblies. The frames have use high-strength steel for greater durability, higher towing capacity and improved ride and handling; the front sections are hydroformed. The bending and beaming stiffness of the frames is increased 92 percent and 20 percent over the model it replaced, with the fully boxed sections enhancing torsional stiffness by a factor of five. Also, larger engine and transmission mounts, coupled with a 125-percent-stiffer front frame structure, provide greater vibration control, while hydraulic body mounts are incorporated under the cab section on extended and crew cab models for a more isolated feel inside.